Pin-type lampholder



Jan. 13, 1959 G. B. BENANDER 2,869,101

PIN-TYPE LAMPHOLDER Filed March 29, 1956 hang er 2,869,101 Patented Jan. 13, 1959 PIN-TYPE LAMPHOLDER George B. Benander, ()aklawn, R. I., assignor to General Electric Company, a corporation of New York Application March 29, 1956, Serial No. 574,841

Claims. (Cl. 339-99) The present invention relates to a lampholder for use in decorative street lighting or as part of outdoor Christmas tree lighting arrangements. This improvement was made to speed the installation of festoon lighting where the conductors are separately insulated and individually supported from each other. The terminal end of the contacts of this lampholder are formed with a sharp pin or point to pierce the insulation of the conductors when a rotary cap is clamped over the conductors.

The art of forming lampholders with pin-type contacts which pierce the insulation of the conductors was quite active back at the turn of the century but there has been very little activity in this field in recent years. A standard pin-type lampholder now used includes three separate parts; namely, the main body or socket portion, a threaded cap for forcing the conductors onto the contact pins, and a wire hook for suspending the lampholder from a suitable messenger or carrier cable. Obviously, the threaded cap must be backed out for more than several complete turns before the wires may be forced into place. Oftentimes, the workman assembling these lampholders to the wires will be standing at the top of a ladder and if he is not careful, the cap will be unscrewed from the socket and possibly dropped, thereby requiring him to discard the lampholder or to take the time to retrieve the missing part.

The present invention comprises a lampholder having a lamp base-receiving socket containing a side and a central contact. The terminal end of each contact extends through the bottom Wall or base of the socket with a pointed end for piercing the insulation of the conductors. The terminal ends of the contacts are located in deep grooves so that the conductors are confined therein. A rotary cap is pivotally mounted on an axis between the conductors and it moves from a position whereby the grooves are opened to a second position displaced 90 therefrom for forcing the conductors onto the pointed ends of the contacts. A tongue and notch formation is provided between the ends of the cap and the outer edges of the bottom wall of the socket for locking the cap in the closed position where the conductors are pierced by the contact pins. A strong twisting force is necessary to close and open the cap, especially when the the conductors are in place. Another feature of my invention which alleviates this situation is the use of a special hook members fastened against rotation on the cap. This hook member extends transversely of the pivotal axis of the cap and may be used in the manner of a wrench to increase the mechanical advantage during the twisting operation. However, when the wires are clamped in place and it is time to support the lampholder from a suitable messenger or carrier cable, the hook member would be bent 90 so that it extends longitudinally of the lampholder for suspending the lampholder in the usual manner.

Accordingly, the principal object of this invention is to provide a pin-type lampholder with a rotary cap which is movable to one-position exposing the pin contacts'and which when twisted through would be in a closed position.

A further object of this invention is to provide a pin-type lampholder which requires only a quarter turn in order to clamp the conductors therewith.

A further object of this invention is to provide a pintype lampholder having a rotary cap that is movable through a quarter turn to clamp the conductors and has a suitable locking means for holding the cap in this closed position.

A still further object of this invention is to provide a novel hook member for the rotary cap of a pin-type lampholder where the hook member serves as a wrench to increase the mechanical advantage necessary to turn the cap to a clamping position while the hook member may later be bent into its proper supporting position.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Figure 1 is a front elevational view of a pin-type lampholder embodying my invention.

Figure 2 is a left side view of the lampholder of Figure 1.

Figure 3 is a top plan view of the lampholder of Figure 2 showing the rotary cap in the closed position.

Figure 4 is a cross-sectional elevational view taken on the line 4-4 of Figure 2.

Figure 5 is a plan view of the lampholder with the rotary cap shown in the open position.

Figure 6 is a view similar to that of Figure 5 with the insulated conductors located therein.

Figure 7 is an enlarged partial view taken on the line 7-7 of Figure 5 showing how the insulated conductor is impaled on the pointed end of the contact terminal.

Figure 8 is another enlarged partial view showing the detail of the wire pierced by the contact pin and held in place by a cam surface on the underside of the rotary cap.

Referring in detail to the drawing and in particular to Figures 1-3, ltl represents a pin-type lampholder embodying my invention which is molded from a suitable electrical insulating material. The main parts of the lampholder are the lamp base-receiving socket 11 which is open at one end, a narrow rotary cap 12 pivotally mounted on the bottom wall of the socket and a hook member 13 of steel strip material which is fixedly secured to the cap. Looking at the cross-sectional View of Figure 4, it will be understood that the self-tapping screw 14 extends through an opening in one end of the hook member 13, then through the cap 12, to be threaded into the opening 15 in the bottom wall 16 of the socket 11. The usual metal screw shell socket (not shown) for an incandescent lamp has been replaced for cost reduction purposes by a side contact 17 of strip material for engaging the screw shell base of a lamp. The lamp base would be supported by the molded threads 18 on the interior of the socket 11 which is a well-known construction in this art. A center contact 19 is provided on the bottom wall of the socket for engaging the central portion of the lamp base to thereby complete the circuit through the lamp.

Figure 8 shows the detail of the terminal end 20 of the center contact 19 extending through the bottom wall 16 of the socket. The terminal ends of the contacts 17 and 19 are identical so that only end 20 of contact 19 will be described in full. A side view of the terminal end 20 is shown in Figure 7 with a pointed tip or pin 21 for piercing the insulation of the wire 22. A small tab 23 is formed on both sides of the pointed pin 21 for holding the contact in the bottom wall of the socket. The tabs of eachcontact are bent in opposite directions as seen in Figure 5 to prevent the contact from moving.

Turning to Figures 4 and 5, the terminal ends of the contacts 17 and 19 are each shown as seated in a deep groove on diametrically opposite sides of the bottom wall of the socket. These grooves are formed by a center post 26 positioned between the terminal ends of the contact, and a pair of side posts 27 adjacent the outer sides of the contact terminals. Looking at the plan view of Figure 5, the grooves 25 are of arcuate shape and centered around the pivot screw 14.

As mentioned before, the rotary cap 12. is pivotally mounted by means of screw 14 to the bottom wall 16 of the socket. The width of the cap is less than the spacing between the grooves so the cap may be turned to expose the terminals and insert the conductors. The under-side of the cap has a pair of cam surfaces 3%? which are adapted to overlie the conductors in the grooves 25 containing the terminal ends of the contacts. This cam 30 serves to impale the conductor on the pointed tip 21 while the sides of the groove confine the conductor in a minimum space, as seen in Figure 8. As best seen in Figure 2, each side post 27 of the bottom wall of the socket has a stepped surface comprising a lower step 31, an upper step 32 and a notch 33 in the lower step adjacent the upper step. Likewise, each end of the cap 12 has a complementary mating surface including a pair of step members 34 and 35 separated by a tongue 36 which seats in the notch 33 in the side post 2'7. This tongue and notch formation serves as a locking means when the cap is in its closed position for holding the lampholder assembled with the conductors 22. It should be understood that there is a certain looseness between the cap and the bottom Wall of the socket along the axis of the screw 14 which permits the tongue 36 of the cap to ride out of the notch 33 and over the lower step 31 until the cap is in the open position of Figure 5. Also, the upper step 32 of the side post cooperates with the tongue 36 of the cap to serve as a stop member so that the cap may only be turned through a quarter circle from the fully open position of Figure 5 clockwise to the fully closed position of Figure 4.

Pin type lampholders, according to my invention are made in several sizes for receiving both an intermediate and a medium size lamp base. A great deal of difiiculty would be experienced, especially in the smaller size lampholders, in twisting the cap 12 into and out of its locked position. My invention includes the additional feature of a novel hook member 13 that is fastened at its inner end 38 by a screw 14. Flanges 35' are arranged on opposite sides of the hook member to prevent the hook from pivoting about the screw 14. As seen in Figure 4, the hook extends transversely of the lampholder so that it may be grasped by the hand to increase the torque exerted on the cap for moving it into its different positions. This hook member acts the same as a wrench or handle while in some competitive constructions a separate wrench is necessary for clamping the conductors in place. However, the lampholder would not hang properly it the hook 13 remained in this transverse position; therefore, it ,is contemplated that the workman will bend the hook at the reduced cross-section it? adjacent the screw 14, as seen in Figures 4 and 5. Then the hook will extend longitudinally of the lampholder, as seen in dotted lines in Figure 4.

Having described above my invention of a novel pintype lampholder which may readily be assembled and disassembled from a pair of separately insulated and individually supported conductors, it should be understood that I have both reduced the cost of manufacture of such lampholders as well as provided the public with a timesaving design which does not require the separation of any of the parts in order to clamp the conductors. The complete lampholder is assembled in the factory and the workmen in the field would have no trouble in placing the wires against the contact pins and using the hook member as a wrench to turn the rotarycap to its closed position.

This design is not only simple to manufacture and reliable in operation but it has the additional feature of decreasing the time necessary for installing the lampholder in its intended manner.

Modifications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiment disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A lampholder comprising a lamp base-receiving portion containing contacts adapted for making electrical connection with a lamp, the terminal end of each contact being pointed to pierce the insulation of a conductor and extending through the base of the lampholder and fixed thereto, a rotary cap of a width less than the spacing between the contact terminals and pivotally mounted on the exterior of the base about an axis between the said termi nal ends, and a side post extending along the outer side of the pointed terminal end of each contact, a tongue and notch formation between the said cap and side post so as to lock the cap over the terminals to hold the conductors in place, and a diagonal groove on the outer side of the cap having a hook member attached in the bottom thereof and extending transversely through the side opening of the groove so that the hook member may serve as a wrench to increase the ease of turning the cap, while the hook member may be bent at a right angle so that the lampholder is capable of being suspended from a suitable supporting member.

2. A lampholder comprising a lamp base-receiving socket having a side and a central contact fixed therein, the

terminal end of each contact being pointed and extending through the base of the socket to lie adjacent opposite side edges of the base, a central post formed on the base between the pointed terminals, and side posts on outer sides of the terminals so that the terminals are disposed in deep grooves between the central and side posts, and a rotary cap of a width less than the spacing between the contact terminals and pivotally mounted on the central post and movable through a quarter turn from a position where the grooves are open to a position in alignment with the side posts for clamping conductors on the pointed terminals, a hook member fixedly secured to the cap and extending sidewardly therefrom to be usable as a wrench for increasing the mechanical advantage for turning the cap, while the hook member may later be bent at a right angle so that the lampholder may be suspended from a suitable support.

3. A lampholder comprising a lamp base-receiving socket having cylindrical side walls and a bottom wall, a side contact and a central contact arranged in the socke the terminal ends of the contacts extending through the bottom Wall and having pointed ends which are seated in deep grooves on the outer surface of the bottom wall so that insulated conductors may be confined directly over the pointed terminals, a rotary cap of narrow width less than the spacing between the contact terminals pivotally mounted on the bottom wall between the pointed terminals and movable from a position exposing the terminals through approximately a quarter turn to a position overlying the terminals, the underside of the cap having a pair of cam surfaces which are adapted to force the conductors onto the pointed terminals, a tongue on each end of the cap for engagement in a notch in the bottom wall to temporarily lock the cap in a closed conductor-clamping position, a hook member fixedly secured to the cap and extending sidewardly therefrom to be usable as a wrench for increasing the mechanical advantage for turning the cap, while the hook member may later be bent at a right angle so that the lampholder may be suspended from a suitable support.

4. A larnpholder with insulation piercing terminals comprising a lamp base-receiving socket having a bottom wall, a side and a central contact arranged in the socket, each contact having a terminal portion that extends through the bottom Wall and has a pointed tip that will pierce the insulation of a single insulated conductor, the terminal tips being diametrically opposed to each other and each located in a separate conductor wire-receiving groove that is of arcuate shape in plan view, both grooves being centered around a common axis, and an outer rotary cap pivotally mounted on the bottom Wall of the socket about a pin fastener on the said common axis of the grooves, the cap being of narrow Width that is less than the spacing between the terminal tips so that in one pivoted position the cap exposes the grooves for assembling the conductors, the cap being turned from this pivoted position through a quarter turn to overlie the conductors, the underside of the narrow cap having a cam surface at each end where each cam surface extends into a separate one of the said arcuate grooves so that when the cap is turned to overlie the conductors, the cam sur- 6 faces on the cap will ride upon the conductors and force them into electrical connection with the terminal tips.

5. A lampholder as recited in claim 4 wherein at least one tongue and notch formation is included between the underside of the cap and the outer surface of the bottom Wall of the socket at one end of the cap to temporarily latch the cap in the closed position overlying the conductors, the cap being loosely mounted for limited sliding action along the axis of the pin fastener so that the tongue on the one member may be raised and lowered out of the notch of the other member when a strong twisting force is exerted on the cap.

References Cited in the tile of this patent UNITED STATES PATENTS 1,697,563 Hollwitz Jan. 1, 1929 1,849,846 McNeil Mar. 15, 1932 2,060,115 Pollock Nov. 10, 1936 2,534,804 Tisgione Dec. 19, 1950 2,559,706 Brooks July 10, 1951 

